If roughly 10% of hypertension cases are resistant to treatment, and, if primary hyperaldosteronism accounts for about 10% of those cases, then the overall prevalence would be around 1%.
Estimates of the prevalence of primary hyperaldosteronism among hypertensive patients have ranged from as high as 20% to as low as 1% in unselected patients.
Researchers determined the prevalence of primary hyperaldosteronism among 1616 consecutive patients who were seen at a Greek hypertension clinic during a 20-year period; all patients had resistant hypertension (uncontrolled on a diuretic and 2 other drugs, and confirmed by home or ambulatory measurements). Aldosterone-to-renin ratios (ARRs) and serum aldosterone levels were measured in all patients under controlled conditions; 338 patients in whom both measures were elevated underwent salt-loading suppression tests and 4-day fludrocortisone tests to confirm primary hyperaldosteronism. All patients with confirmed primary hyperaldosteronism received trials of spironolactone monotherapy, with other drugs added as required to control blood pressure.
Primary hyperaldosteronism was confirmed in 182 patients (53.8% of those with elevated ARR and 11.3% of patients overall). All of these patients had statistically significant blood pressure reductions within 2 to 4 weeks of starting spironolactone monotherapy, and all achieved target blood pressure on spironolactone either alone (37%) or in combination with other agents.
Comment: If roughly 10% of hypertension cases are resistant to treatment, and if primary hyperaldosteronism accounts for about 10% of those cases (as in this study), then the overall prevalence would be around 1%. Nevertheless, case-finding is important, because primary hyperaldosteronism seems to confer a higher risk for target organ damage than does essential hypertension, and hyperaldosteronism can be treated easily. Hypokalemia measurements are neither sensitive nor specific; aldosterone-to-renin ratios and serum aldosterone level are nonspecific, and definitive diagnosis (e.g., by performing salt-loading suppression testing, possibly after stopping certain antihypertensive drugs) is costly and potentially risky. An editorialist suggests referral to a specialty center for patients with elevated ARRs and plasma aldosterone levels or for patients who do not respond to empirical trials of aldosterone blockers.
— Bruce Soloway, MD
Published in Journal Watch General Medicine July 23, 2008
Douma S et al. Prevalence of primary hyperaldosteronism in resistant hypertension: A retrospective observational study.